LANCASTER TWP — A tanker truck carrying a load of milk overturned at 1 p.m. Monday on Interstate 79, which caused milk to leak into Yellow Creek on the east side of the interstate. The truck was northbound about a half mile north of the Seneca Valley School District’s secondary campus when it overturned. Northbound traffic was backed up for a mile or more at 3:30 p.m. One lane remained open. The driver, Adam Kuronya, 28, of Birdsboro, Berks County, was not injured, according to state police from Butler. Police said Kuronya pulled the rig onto the western shoulder of the road to avoid hitting slowing traffic. The rig rolled onto its passenger side. A small stream of bright white milk trickled into Yellow Creek, about a quarter-mile north of Yellow Creek Road’s intersection with Little Creek Road. While milk may seem harmless, the county Hazardous Materials Response Team and state Fish and Boat Commission experts were called to the scene because of the spill. Sgt. Tom Tarkowski, assistant regional manager at the Fish and Boat Commission’s northwest region in Meadville, said milk can be dangerous if in natural waters because it is an oxygen-grabbing substance. That could cause a lack of oxygen in the water, which can kill aquatic life, Tarkowski said. About 3:15 p.m., firefighters were using a rope to ease down the steep bank from I-79 to the creek, where they laid two large tarps. The four men also dug a makeshift dam where the milk entered the babbling stream. One firefighter shoveled dirt from the creek’s bank onto the rivulet of milk after the tarps had been laid. Tarkowski said he understood the men were creating a temporary containment pond for the milk to prevent it from running into the stream. It was not immediately known how much milk entered the creek or if any aquatic life had been affected.